If she uses an iPhone, you can get a HK iTunes voucher. For food I would ask her what she likes to eat and if she does mention chocolate, get a small box of luxury chocolate from La Maison du Chocolat or Godiva. They will not make her fat as she can space them out a bit, being so rich. Also, this will make her think of you at least once a day for 6 days after as she has her little daily treat.
Something that might really get her in the mood, if she really is special, is to send flowers a few hours before you arrive
You might want to goggle the number of flowers to send a Chinese women because these might have special meaning to her.
I have not gone this direction yet, but if she was a real stunner and I really had a good time with her I might waste some cash and get some jewelry or a designer watch - but I really doubt I would ever go that far.